Generally, the organic waste such as food waste and sewage sludge had been processed by reclaiming land. However, the organic waste may be easily decomposed due to its high water-content feature to produce bad smell and waste water. Furthermore, the secondary environmental pollution such as the underground contamination may occur because much of leachate flows in the landfill.
So, the carbonization process should be performed after removing the moisture (water) in the organic waste in order to make the high water containing organic waste be the recycling material.
The carbonization process is performed under the anaerobic condition or low-oxygen atmosphere (2˜4%) where the organic material is pyrolized by heating through an external heating source to fix carbon on a final product. The most organic waste may be recycled by means of the carbonization process.
With respect to the above mentioned carbonization process, the Korean Publication Patent 2014-002807 disclosed the sludge carbonization system including first dryer where a sludge had been dried, a carbonization unit for carbonizing the dried sludge, and a heated-air supply unit for supplying a heated-air to the dryer and the carbonization unit.
This technology has a dryer using the heated-air which had been burned from a fuel such as LPG and LNG to dry the 8 wt %˜30 wt % water containing sludge to move it to the carbonization unit. However, the temperature of the heated-air is not steady so that it cannot dry the inside of the sludge. So, the final product has a low caloric value and a low quality.
Therefore, it is necessary to develop a bio-char producing system which can produce the final product having a high caloric value and minimum consumption energy.